Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-02-25
2002-03-19
Hall, Carl E. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S840000
Reexamination Certificate
active
06357106
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for mounting parts by means of conductive paste, and an IC card and its manufacturing method.
BACKGROUND OF THE INVENTION
In manufacturing a non-contact IC card comprising a coil and an IC chip, and transferring data with external via the coil, coils such as a copper wire-wound coil, coils of printed conductive pastes, e.g. silver paste, and coils of etched metal foils, e.g. copper foil, are used as a coil, and in particular, a method for forming a circuit pattern by printing conductive pastes has become popular.
FIGS. 10
to
13
show a conventional IC card and its manufacturing method.
As shown in
FIG. 10
, the conventional IC card is constructed such that a coil pattern
2
is formed on the first substrate
1
a
by means of a conductive paste, and a connecting pad
6
provided at the external end
3
a
of this coil pattern
2
and a connecting pad
6
provided at the internal end
3
b
are electrically connected with electrodes of an IC chip
4
.
The manufacturing process is shown in FIG.
11
.
Firstly, in step
1
, a circuit pattern including the coil pattern
2
is printed on the surface of the first substrate
1
a
by means of the conductive paste.
In step
2
, the printed circuit pattern is heated for 10 minutes at the temperature of 120° C. to cure the conductive paste.
In step
3
, as shown in FIG.
12
(
a
), an anisotropic conductive sheet
9
is stuck on the connecting pad
6
of the circuit pattern.
In step
4
, the anisotropic conductive sheet
9
is heated for 5 seconds at the temperature of 100° C. and temporally pressed.
In step
5
, parts such as the IC chip
4
and capacitors are mounted on the temporally pressed anisotropic conductive sheet
9
.
A bump
10
is formed on an mounting surface of the parts
16
via an electrode pad
7
, as shown in FIG.
12
(
b
), and the bump
10
is electrically connected with the connecting pad
6
via the anisotropic conductive sheet
9
, as shown in FIG.
12
(
c
).
Particularly, the IC chip
4
is placed such that, as described above, the connecting pads
6
provided at the external end
3
a
and the internal end
3
b
of the coil pattern
2
are electrically connected with the electrode pad
7
of the IC chip
4
.
And, the bump
10
, formed by using wire bonding and plating, in particular, plating using solder, gold, silver, and copper is used.
In step
6
, the anisotropic conductive sheet
9
is heated for 30 seconds at the temperature of 200° C. to be cured for pressing the parts
16
as shown in FIG.
12
(
d
).
Then in step 7, by applying a second substrate to the first substrate
1
a
for laminating processing, as shown in
FIG. 13
, the IC card can be obtained in which the connecting pads
6
and the bump
10
provided on the parts
16
are electrically connected via the anisotropic conductive sheet
9
.
5
denotes a capacitor connected in parallel to the coil pattern
2
, and
1
b
denotes the second substrate.
However, since it is typical to use inexpensive thermoplastic resin such as polyethylene terephthalate and vinyl chloride for the first substrate
1
a
and the second substrate
1
b,
there is a problem that, in the conventional manufacturing process described above, these substrates having less heat resistance are susceptible to degradation due to the high temperature of 200° C. or more when pressing the anisotropic conductive sheet
9
in step
7
.
Also, there is a problem that using a substrate having superior heat resistance instead of the thermoplastic resin increases the costs.
And there is a further problem that the connecting resistance and the number of steps are increased, and the productivity is lowered, and costs are increased because the anisotropic conductive sheet is used for securing the parts. And it is the same with the case of using an anisotropic conductive particle instead of the anisotropic conductive sheet.
And, when the parts
16
are mounted in step
5
, there is a problem that it is needed to draw a plurality of coil patterns
2
between the terminals of the IC chip
4
, as shown in
FIG. 10
, since the external end
3
a
and internal end
3
b
of the coil pattern
2
are constructed not so as to be linked to each other in a single brush stroke.
DISCLOSURE OF THE INVENTION
The present invention provides a method for mounting parts, and an IC card and its manufacturing method, that is capable of solving the problems, reducing the number of steps, increasing the productivity to lower costs, and miniaturizing the chip.
To solve the problems, the method for mounting parts according to the invention is characterized in that parts to be mounted are placed on the circuit pattern before the conductive paste is cured, and then mounted by curing the conductive paste.
According to the invention, it is possible to lower costs due to the reduction of steps, the good productivity, and the possibility of the low temperature mounting of the parts, and further to contribute to the miniaturization of the IC chip.
The method for mounting parts according to a first embodiment of the invention is characterized in that a circuit is formed by printing a circuit pattern on a substrate by means of a conductive paste, placing parts on the circuit pattern such that its electrode is connected to the circuit pattern, and curing the conductive paste to electrically connect the electrode with the circuit pattern.
According to this configuration, it is possible to mount parts at low temperatures and reduce steps to lower costs.
The method for mounting parts according to a second embodiment of the invention is characterized in that a circuit is formed by printing a circuit pattern on a substrate by means of a conductive paste, placing parts having a pump formed on its electrode pad on the circuit pattern such that its electrode is connected to the circuit pattern, and curing the conductive paste to electrically connect the electrode to the circuit pattern.
The method for mounting parts according to a third embodiment of the invention is characterized in that the bump is formed of metals or plating.
The IC card according to a fourth embodiment of the invention is a non-contact IC card comprising a coil and an IC chip, and transferring data with external via the coil, and is characterized in that a first electrode of the IC chip for processing signals received from the coil is connected to an internal end of a coil pattern formed on the substrate, and an external end of the coil pattern and a second electrode of the IC chip are connected via a jumper wiring means.
According to this configuration, it is possible to reduce manufacturing steps and lower costs, by directly mounting parts on the conductive paste before it is cured, and then by curing the conductive paste, and it is possible to stabilize the circuit pattern, as well as ensure an electrical connection between the circuit pattern and the parts.
And, an anisotropic conductive sheet is not required to provide, and it becomes possible to various parts at low temperature, and also lower resistance can be realized.
And further, it is not required to draw a plurality of coil patterns between the terminals of the IC chip, so that it is possible to use an IC chip having narrow space between the terminals to miniaturize the IC card.
The IC card according to a fifth embodiment of the invention is characterized in that the jumper wiring means is a wire having an insulatingly covered middle portion and ends with exposed conductive portions, or a foil constituted of an insulating sheet with a metal film.
The method for manufacturing the IC card according to a sixth embodiment of the invention is characterized in that, in manufacturing a non-contact IC card comprising a coil and an IC chip, and transferring data with external via the coil, it comprises the steps of printing the circuit pattern including the coil pattern on the substrate by means of the conductive paste, placing the IC chip on the circuit pattern such that its electrode is connected to the circuit pattern, placing the jumper wiring means for
Akiguchi Takashi
Harada Yutaka
Murakami Shinji
Oku Mitsumasa
Sato Ken'ichi
Hall Carl E.
Matsushita Electric - Industrial Co., Ltd.
Parkhurst & Wendel L.L.P
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